# CVE-2026-13042: RPB Chessboard <= 8.1.2 - Unauthenticated Stored Cross-Site Scripting via Comment Content

> Unauthenticated attackers can inject arbitrary scripts via comment content in the RPB Chessboard plugin, leading to potential account takeover.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Jul 2026
- **Updated:** 18 Jul 2026
- **Also known as:** GHSA-23qv-c3w3-qc96

## What is CVE-2026-13042?

CVE-2026-13042 is a high-severity cross-site scripting vulnerability in yo35 RPB Chessboard, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The RPB Chessboard plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content in all versions up to, and including, 8.1.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. WordPress's save-time kses sanitization does not mitigate this issue because the crafted payload uses only kses-allowed tags and attributes (such as an &lt;a&gt; element with title and href), and the dangerous attribute-breaking HTML is synthesized entirely at render time by the plugin's own comment_text filter.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-13042?


## How do I fix CVE-2026-13042?

No fix has been published for CVE-2026-13042 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-13042 being exploited?

There is no known exploitation of CVE-2026-13042 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-13042 and fix it if it is affected.

What it is: CVE-2026-13042 is a high-severity cross-site scripting vulnerability in yo35 RPB Chessboard, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-13042 in the wild and no public exploit code.

Affected product: yo35 RPB Chessboard. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-13042/ (Markdown: https://insights.sbomify.com/CVE-2026-13042/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-13042
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-13042
- OSV: https://osv.dev/vulnerability/CVE-2026-13042

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-13042/
Summaries are generated and may contain mistakes; the official description above is the record.